Cost-effectiveness in hospital infection control--lessons for the 1990s

Soap, water, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2): an ancient handwashing strategy for preventing dissemination of a novel virus

Public Health Agencies worldwide (World Health Organization, United States Centers for Disease Prevention & Control, Chinese Center for Disease Control and Prevention, European Centre for Disease Prevention and Control, etc.) are recommending hand washing with soap and water for preventing the dissemination of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. In this review, we have discussed the mechanisms of decontamination by soap and water (involving both removal and inactivation), described the contribution of the various components of formulated soaps to performance as cleansers and to pathogen inactivation, explained why adherence to recommended contact times is critical, evaluated the possible contribution of water temperature to inactivation, discussed the advantages of antimicrobial soaps vs. basic soaps, discussed the differences between use of soap and water vs. alcohol-based hand sanitizers for hand decontamination, and evaluated the limitations and advantages of different methods of drying hands following washing. While the paper emphasizes data applicable to SARS-CoV-2, the topics discussed are germane to most emerging and re-emerging enveloped and non-enveloped viruses and many other pathogen types.

From lighthouse to hothouse: hospital hygiene, antibiotics and the evolution of infectious disease, 1950-1990

Upon entering clinical medicine in the 1940s, antibiotic therapy seemed to complete a transformation of hospitals that originated in the late nineteenth century. Former death sinks had become harbingers of therapeutic progress. Yet this triumph was short-lived. The arrival of pathologies caused by resistant bacteria, and of nosocomial infections whose spread was helped by antibiotic therapies, seemed to be intimately related to modern anti-infective therapy. The place where such problems culminated were hospitals, which increasingly appeared as dangerous environments where attempts to combat infectious diseases had instead created hothouses of disease evolution. This paper will focus on one aspect of that history. It caused clinical medicine and hospital hygiene in particular to pay attention to a dimension of infectious disease it had previously paid little attention to thus far: The evolution of infectious disease-previously a matter of mostly theoretical interest-came to be useful in explaining many phenomena observed. This did not turn hospital hygienists into geneticists, though it did give them an awareness that the evolution of infectious disease in a broad sense was something that did matter to them. The paper advances its argument by looking at three phases: The growing awareness of the hospital as a dangerous environment in the 1950s, comprehensive attempts at improving antibiotic therapy and hospital hygiene that followed from the 1960s and lastly the framing of such challenges as risk factors from the 1970s. In conclusion, I will argue that hospital hygiene, being inspired in particular by epidemiology and risk factor analysis, discussed its own specific version of disease emergence and therefore contributed to the 1980s debates around such topics. Being loosely connected to more specialized studies, it consisted of a re-interpretation of infectious disease centred around the temporality of such phenomena as they were encountered in day-to-day dealings of clinical wards.

Hospitalization before surgery and subsequent risk of infective complications after radical cystectomy: A population-based analysis

INTRODUCTION

The length of stay prior to surgery increases the risk of postoperative infections (PIs) in several surgical settings, such as cardiac, orthopedic, and general surgery. However, data for urological oncology procedures are limited. We examined PI rates after radical cystectomy (RC) according to the length of stay prior to RC (LOSPRC).

MATERIALS AND METHODS

A total of 24,242 patients with bladder cancer treated with RC between 1998 and 2013 were abstracted from the National Inpatients Sample database. We evaluated changes over time in LOSPRC (0 vs. 1 vs. 2 days or more) and tested its effect on PI rates. Multivariable logistic regression analyses were adjusted for the year of surgery, sex, age, ethnicity, comorbidities, hospital location, teaching status, hospital surgical volume, and number of hospital beds.

RESULTS

Overall, 19,401 (80.0%), 3,990 (16.5%), and 851 (3.5%) individuals with LOSPRC of 0, 1. and 2 or more were identified. The proportion of LOSPRC 0 patients increased from 61.4% in 1998 to 91.0% in 2013 (P<0.001), whereas the opposite trend was observed for LOSPRC 1 and 2 or more. In multivariable logistic regression analyses predicting PIs, LOSPRC of 1 (odds ratio: 1.38; 95% CI: 1.25-1.53; P<0.001) and LOSPRC of 2 or more (odds ratio: 2.15; 95% CI: 1.81-2.55; P<0.001) achieved independent predictor status.

CONCLUSIONS

A delay in surgery as short as 1 day significantly increases the risk of PIs after RC. In consequence, same day of admission surgery policies should be further promoted to reduce the risk of PIs.

Cost-Effectiveness of Perioperative Mupirocin Nasal Ointment in Cardiothoracic Surgery

Objective:

To assess the cost-effectiveness of perioperative intranasal application of mupirocin calcium ointment in cardiothoracic surgery.

Design:

Cost-effectiveness analysis based on results of an intervention study with historical controls.

Setting:

University Hospital Rotterdam, a tertiary referral center for cardiac and pulmonary surgery.

Patients:

Consecutive patients undergoing cardiothoracic surgery between August 1, 1989, and February 1, 1991 (control group, n=928), and between March 1, 1991, and August 1, 1992 (intervention group, n=868).

Intervention:

Perioperative nasal application of mupirocin calcium ointment started on the day before surgery, continued for 5 days, twice daily.

Results:

Postoperative costs were increased significantly in patients with a surgical-site infection (SSI), compared with uninfected patients (P<.001). Mean SSI-attributable costs were estimated at $16,878 (95% confidence interval, $15,575-$18,181). The incidence of SSIs was 7.3% in the control group and 2.8% in the intervention group, mupirocin effectiveness being 62%. The costs of mupirocin were $11 per patient. Thus, the savings per SSI prevented were $16,633. To validate this comparative estimate of SSI-attributable costs, a noncomparative analysis of the postoperative length of stay (POLS) was performed, according to the Appropriateness Evaluation Protocol. Approximately 50% of the comparative SSI-attributable POLS were judged SSI-attributable in the noncomparative analysis. Sensitivity analyses, testing for the robustness of our conclusions, indicated that the presented model is rather insensitive to variations in the incidence of SSIs and for the effectiveness and costs of mupirocin. SSI-attributable costs were shown to be the only variable with substantial effect on the cost-effectiveness ratio. Perioperative mupirocin would result in net costs instead of savings only if SSI-attributable costs were less than $245.

Conclusions:

SSIs in patients undergoing cardiothoracic surgery are associated with a substantial increase in postoperative costs. Provided that perioperative mupirocin reduces the SSI rate, this measure will be highly cost-effective in most centers providing cardiothoracic surgical services.

Epidemiologic Study of Nosocomial Urinary Tract Infections in Saudi Military Hospitals

A case-control study of patients with and without confirmed UTI was performed to identify risk factors for nosocomial UTI. Duration of hospitalization, unit of admission, history of diabetes mellitus or debilitating diseases, and duration and number of urinary catheters were independently associated with increased risk of nosocomial UTIs.

The Impact of Hospital Volume on the Development of Infectious Complications After Elective Abdominal Aortic Surgery in the Medicare Population

Objective: A relationship exists between higher hospital volume and lower mortality, yet the impact of hospital volume on infectious complications after elective abdominal aortic aneurysm (AAA) repair is unknown. Methods: The Medicare database (2005-2007) was utilized. Top 10% for volume were categorized as high-volume (HV) and compared to low-volume (LV) centers for infectious complications and utilization. Results: A total of 42 155 endovascular aneurysm repair (EVAR) and 17 210 open AAA were identified. Mortality in HV was significantly lower than in LV after EVAR and open AAA. After EVAR, HV had lower than LV rates of overall infection (3.10% vs 3.51%; P = .021), PNA (0.94% vs 1.27%, P = .002), and sepsis (0.31% vs 0.45%; P = .03). Length of stay (LOS) and total hospital charges were significantly lower at HV compared to LV after both EVAR and open AAA. Conclusion: For Medicare beneficiaries, undergoing elective AAA repair at hospitals performing higher volume significantly reduced postoperative infectious complications and hospital resource utilization. Further analysis identifying systematic reasons for disparities may offer cost savings and improve outcomes.

In-hospital delay of elective surgery for high volume procedures: the impact on infectious complications

BACKGROUND

Development of infectious complications after high volume elective surgical procedures imposes a significant clinical burden to the United States population. This study evaluated the association of in-hospital delay of elective procedures and the subsequent impact on infectious complications after coronary artery bypass graft (CABG) surgery, colon resection, and lung resection.

STUDY DESIGN

The Nationwide Inpatient Sample was queried between 2003 and 2007, and patients who developed postoperative infectious complications were identified. Time to elective surgery in days from admission was calculated: 0, 1 day, 2 to 5 days, and 6 to 10 days. Infectious complications evaluated included pneumonia, urinary tract infections, postoperative sepsis, and surgical site infections. Chi-square, multivariable logistic regression analyses, analysis of variance, and Cochran-Armitage trend test were used.

RESULTS

There were 87,318 CABG procedures, 46,728 colon resections, and 28,960 lung resections evaluated. Total infection rates significantly increased after elective surgery delays: CABG: 0 days, 5.73%;1 day, 6.68%; 2 to 5 days, 9.33%; 6 to 10 days,18.24%; colon resections: 0 days, 8.43 %;1 day, 11.86%; 2 to 5 days,15.79%;6 to 10 days,21.62%; and lung resections: 0 days, 10.17%;1 day, 14.53%; 2 to 5 days, 15.53%; 6 to 10 days, 20.56%, p < 0.0001 for all trends. Trends for increasing infections after delay were significant for pneumonia and sepsis for all procedures (p < 0.0001); urinary tract infections and surgical site infections significantly increased after CABG and colon resection. Age 80 years and older, female gender, black and Hispanic race or ethnicity, and comorbidities including congestive heart failure, chronic pulmonary disease, and renal failure were associated with delay in surgery. Postoperative hospital mortality after delayed procedures was also greater. Mean cost increased after all procedures with delays: CABG, from $25,164 to $42,055 (p < 0.0001); colon resections, from $13,660 to $25,307) (p < 0.0001); and lung resections, from $18,519 to $25,054 (p < 0.0001).

CONCLUSIONS

In-hospital delay of elective surgery from the day of admission was associated with a significant increase in infectious complications and mortality. This delay was also associated with a significant increase in hospital cost. Future policy directed toward preventing in-hospital delay of elective surgery may offer significant cost savings and decrease infectious complications after elective surgery.

Using Cost of Infection as a Tool to Demonstrate a Difference in Prophylactic Antibiotic Efficacy: A Prospective Randomized Comparison of the Pharmacoecomonic Effectiveness of Ceftriaxone and Cefotaxime Prophylaxis in Abdominal Surgery

The purpose of this study was to test the hypothesis that cost, as well as frequency of infection, could be used to demonstrate a difference in the performance of prophylactic antibiotics. In a prospective, randomized, double-blind study, 1013 patients undergoing abdominal surgery were given 1 g of intravenous ceftriaxone (R) or cefotaxime (C) at induction of anesthesia, and an additional 500 mg of metronidazole for colorectal surgery. Infection was checked for during the hospital stay and at 30 days postoperatively. The inpatient, outpatient, and community costs of infection were prospectively collected. The frequency of wound infection for appendectomies when additional metronidazole was not administered was greater with cefotaxime (R 6%, C 18%, p < 0.05), but the cost of infection was the same (average cost R $994 +/- SD $1101, C $878 +/- $1318). For all other procedures, the frequency of wound infection was similar (R 8%, C 10%), but the cost was less with ceftriaxone (R $887 +/- $1743, C $2995 +/- $6592, p < 0.05). Ceftriaxone decreased the frequency but not the cost of chest and urinary infection (frequency R 6%, C 11%, p < 0.02, cost R $1273 +/- 2338, C $1615 +/- 4083). Differences in both the frequency and cost of all infection are also presented. Ceftriaxone decreased either the frequency or the cost of different postoperative infections. The cost of infection can increase the discriminatory power of trials comparing antibiotic effectiveness.

The appropriate use of gloves to reduce allergies and infection

Twenty years ago, the wearing of gloves for non-sterile procedures was viewed as insulting to the patient as it made him/her feel 'unclean'. Today, gloves are worn for all procedures and are often wastefully used. There must be a fine balance between inappropriate and appropriate use of gloves and between the use of latex gloves for comfort and fine movements vs the potential for latex allergies. This article will review the use of synthetic and latex gloves and examine some of the related issues.

Use of gloves in the community: why, when, which and how?

The use of gloves has become routine since the early 1980s. It is recognized that they have an important part to play in the protection of both staff and patient/clients in the prevention of cross-infection. However, as choices relating to glove usage have increased over the years, health-care staff need to adopt a risk assessment approach, considering why, when, which and how gloves should be used. This article outlines the different types of gloves available and when they should be used.

Economic analysis of nosocomial infections in a Turkish university hospital

Nosocomial infections constitute an important health problem with morbidity, and high mortality, prolongation of hospital stay, and increased costs of direct patient care. This study was conducted in Hacettepe University Hospital in order to determine the cost of nosocomial infections and length of hospitalization by matching infected patients with uninfected controls. Data collected from 102 individuals with nosocomial infection (group A) and 102 controls without nosocomial infection (group B) were recorded by using a computer program (dbase IV). Urinary tract infections, surgical wound infections and bacteremias were the most common nosocomial infections. Patients were generally located in Internal Medicine, Neurosurgery, General Surgery Clinics. The mean total length of stay was 35.1 and 14.8 days for group A and group B, respectively (p<0.001). The average hospital cost was US $2280 for group A, and US $698 for group B (p<0.001). Mortality rates were 19.6% for patients with nosocomial infections and 2.9% for uninfected controls (p<0.0001). We conclude that the high economic expense which nosocomial infection represents justifies measures to control this entity.

Prolongation of hospital stay and extra costs due to hospital-acquired infection in a neonatal unit

A case-control study to evaluate the mean extra stay and corresponding cost of neonates acquiring a hospital-acquired infection (HAI) was performed on all patients admitted to a neonatology unit and discharged alive in 1994. Cases were identified from medical records. Controls were matched to cases for birthweight, gestational age, mode of admission to the unit, previous stay in an intensive care unit and presence of a central venous catheter. Costs were taken as those of the extra days attributable to HAI, i.e. the mean difference in the length of stay between cases and controls. Among a cohort of 616 neonates, 34 (5.5%) had one or more HAIs (average = 1.1). The mean extra cost per infected case was 52,192 FF (US$10,440), corresponding to 5.2 extra days in hospital.

Review of clinical activity by microbiologists

A data form was devised and used to collect information on clinical cases involving a microbiologist. From the results a relational database management system was created. Of a total of 280 interventions, 137 (49%) were proactive, and in 118 (86%) of these cases the advice given was accepted. The majority of the patients in these cases showed subsequent improvement. Of all the interventions, the given advice was acted upon in 235 (84%), in 22 (8%) it was not and for the remainder this information was not available. This study was a simple method of gaining information on the clinical involvement of the microbiology department of a large city hospital. It provides a reference point from which further research and audit can be based.

A clinical infection control audit programme: evaluation of an audit tool used by infection control nurses to monitor standards and assess effective staff training

In today's competitive market infection control teams are under increasing pressure from purchasing authorities to provide hard data on quality issues. The initial aim of this study was to determine whether a modified form of the audit system used to monitor infection control standards in Derbyshire could be used effectively across three district health authorities. Infection control nurses in each of the study districts have different approaches to training with only Stafford using a link nurse system. Our additional aim therefore was to examine the relationship between the knowledge base of nursing staff and their ward audit score, and to determine whether wards with link nurses achieved significantly higher scores. To establish this a questionnaire was devised and completed by three different grades of staff on each ward at the time of the audit. These results were fed back to the wards and to managers by the infection control nurse, and an action plan given with a review date where applicable. Results of the study indicated that the audit tool could be used effectively in any district but would need modifying for psychiatric departments. The value of education in improving standards of infection control was clearly demonstrated. An important finding in Stafford was that wards with link nurses obtained significantly higher scores. The value of using such a clinically based audit will be discussed.

Microbial contamination of brushes used for preoperative shaving

Microbial contamination of brushes used for preoperative shaving was investigated. Of the 24 brushed examined, 18 were contaminated with 10(6)-10(9) colony forming units (cfu) per brush. Non-fermentative Gram-negative bacilli such as Pseudomonas aeruginosa and Xanthomonas maltophilia, and yeast-like fungi such as Candida parapsilosis were the primary contaminants. The mean bacterial count on the skin after the use of contaminated brushes (having a mean bacterial count 2.2 x 10(8) cfu) in 14 subjects was 4.6 x 10(5) cfu 25 cm-2, which was about 100 times (p less than 0.001) the control level. Contaminated brushes could not be disinfected with 80% ethyl alcohol, 0.1% sodium hypochlorite or 0.5% chlorhexidine. These findings suggest that the use of brushes should be avoided for preoperative shaving with a razor, and that sterile gauze and shaving foam should be used instead of a brush and soap.

Prevention of nosocomial infection in critically ill patients by selective decontamination of the digestive tract. A randomized, double blind, placebo-controlled study

OBJECTIVE

To evaluate the effect of a method of Selective Decontamination of the Digestive Tract (SDD) on colonization, nosocomial infection (NI), bacterial resistance, mortality and economic costs.

DESIGN

Randomized, double blind, placebo controlled study.

SETTING

Polyvalent intensive care unit (ICU) of a tertiary care hospital with 27 beds.

PATIENTS

101 patients with > 3 days of mechanical ventilation and > 5 days of stay, without infection at the start of the study. 47 belonged to the Treated Group (TG) and 54 to the Placebo Group (PG).

INTERVENTIONS

The TG was given Cefotaxime i.v. (6 g/day) for the first four days and an association of Polymyxin E, Tobramycin and Amphotericin B at the oropharyngeal and gastrointestinal level throughout the whole stay.

RESULTS

In the TG, colonization by gram-negative agents at oropharyngeal, tracheal and gastrointestinal level fell significantly. There was a significant drop in the overall, respiratory and urinary NI (26% vs 63%, p < 0.001; 15% vs 46%, p < 0.001; 9% vs 31%, p < 0.01). The overall mortality and NI related mortality was less in the TG (21% vs 44%, p < 0.05; 2% vs 20%, p < 0.01). The economic costs, mechanical ventilation time and length of stay were similar. The percentage of bacterial isolations resistant to Cefotaxime and Tobramycin was greater in the TG (38% vs 15% and 38% vs 9%, p < 0.001).

CONCLUSIONS

colonization by gram-negative bacilli, NI and the mortality related to it can be modified by SDD. Continuous bacteriological surveillance is necessary.

Prolongation of hospital stay and extra costs due to ventilator-associated pneumonia in an intensive care unit

A prospective cohort study was performed to determine the prolongation of stay and the extra costs incurred due to the occurrence of ventilator-associated pneumonia in intensive care unit patients. Over a 16-month period a sample of 270 consecutive adult patients from a large university anesthesiological intensive care unit requiring ventilation therapy for more than 24 hours was analyzed. A matching procedure using multiple control patients without pneumonia per infected patient (= case) was employed. Of 78 cases 21 (26.9%) died and were excluded from the matching procedure as well as 23 (29.5%) for whom suitable controls could not be found. The maximum number of controls per case was five. The mean added stay was calculated to be 10.13 days and the extra costs attributable to the prolongation of stay were 14,253 German Marks (US$8,800) per patient, demonstrating considerable added stay and costs due to ventilator-associated pneumonia acquired during intensive care. However, it should be taken into account that the calculations for excess stay and costs are based on a subset of rather ill patients and thus cannot generally apply to all ventilated patients and that cases were excluded which could not be matched.

Bacterial contamination and the effect of filters in anaesthetic circuits in a simulated patient model

In order to investigate bacterial contamination of anaesthetic breathing circuits and means of prevention of this, six different laboratory experiments were performed. These experiments involved the bacterial contamination of Dräger Narkose Spiromat 650 and Dräger AV-1 circle system circuits and of an isolated soda lime carbon dioxide absorber. The effects of anaesthetic gas, gas flow rate and the incorporation of a hydrophobic membrane heat and moisture exchanging bacterial/viral filter (HMEF) at the patient end of these circuits were investigated. It was found that without a HMEF the whole interior of the anaesthetic circuits became contaminated with bacteria. Components closest to the simulated patient showed the highest levels of contamination. Higher gas flows were associated with decreased levels of circuit contamination, presumably because more bacteria were expelled from the system. Halothane (1 volume %) and soda lime were not found to have any demonstrable bactericidal action. The presence of a HMEF between the simulated patient and the Y-piece prevented any detectable contamination from reaching the circuit. Consequently, the presence of a HMEF provides protection of the anaesthetic circuit as well as other patients, healthcare workers and the environment.

Cost improvements through the establishment of prudent infection control practices in a Brazilian general hospital, 1986-1989

OBJECTIVES

To review procedures currently practiced in a Brazilian general hospital and to eliminate ineffective and inefficient practices. To measure the resulting cost improvements based on rigid hospital financing control.

DESIGN

Implementation of surveillance and control programs and prevalence surveys to detect ineffective and inefficient practices.

PARTICIPANTS

The study institution is a 130-bed general care facility affiliated with the Brazilian federal government. There were approximately 4,600 admissions per year during the study period (1986-1989).

RESULTS

Instituting infection control measures and eliminating ineffective practices resulted in the following: an overall decrease in wound infection rates from 24.4% in 1987 to 3.45% in 1989; a 71% reduction in the global incidence of infection in the intensive care unit; a 74% reduction in the surgical prophylactic use of antibiotics; and a total savings of approximately $2 million (US dollars).

CONCLUSIONS

During the period from 1986 to 1989, the infection control committee was able to decrease the overall wound infection rate from 24.4% in 1987 to 3.45% in 1989. This eliminated special health problems and improved patient care and cost-effectiveness for our hospital.

Selective decontamination of the digestive tract (SDD) in intensive care patients: a critical evaluation of the clinical, bacteriological and epidemiological benefits

Twenty trials (17 controlled and three observational cohort studies) on selective decontamination of the digestive tract (SDD) have been undertaken to date. SDD is defined as a technique which aims to eradicate carriage of disease-causing microorganisms by means of lethal oropharyngeal and faecal antimicrobial concentrations. The SDD concept and the criteria for the choice of the antimicrobials used in the SDD programme are explained. Abolition of the carrier state is thought to provide clinical, bacteriological and epidemiological benefits. Infection-specific morbidity and mortality, emergence of antibiotic resistance and outbreaks are the main endpoints evaluated in this review. Of the 15 controlled studies that considered carriage, 14 demonstrated a significant reduction of Gram-negative bacillary (GNB) carriage. Severe infections, including pneumonia and septicaemia, caused by enterobacteria and pseudomonads have been virtually eliminated in these trials. Five of the 12 centres that evaluated mortality showed a significant decrease among patients who received SDD. Two recent trials describe the control of an outbreak with a multiresistant Klebsiella by SDD. There are three indications for the use of SDD so far: (i) in trauma patients; (ii) in certain elective surgical procedures including liver transplantation and oesophageal resection; and (iii) in control of outbreaks of ICU infection. Future lines of research may include a properly designed trial with mortality as endpoint and studies on the transfer of SDD from the ICU into the ward as part of prophylaxis in major surgery.

Evaluation of the costs and benefits of reducing hospital infection

The techniques of economic evaluation have now been widely applied in health care. These techniques assess the value for money from interventions by comparing their costs and consequences. Since measures to reduce hospital infection normally result in costs they should, in principle, be subjected to economic evaluation. This paper outlines the essential elements of economic evaluation and distinguishes between different forms of analysis. It also discusses a number of evaluations of infection control measures undertaken to date. The recurring methodological weaknesses in current studies are identified and improvements suggested. Finally, the practical relevance of such studies in the current cost-conscious health care environment is discussed.

Feasible and desirable future targets for reducing the costs of hospital infections

The authors propose that there are, in general, five methods to reduce the costs of hospital infection: reduce the incidence, reduce the morbidity causing prolonged illness, reduce hospital stay, reduce the costs of currently effective preventive and control measures, and stop all ineffective measures. The feasible and desirable components of these methods are described.

Review of available trials of selective decontamination of the digestive tract (SDD)

Eighteen studies on Selective Decontamination of the Digestive Tract (SDD) have been published up to now. A statistically significant reduction of infection rate was found in fourteen out of the fifteen controlled studies. Although all the studies were designed to evaluate infection-related morbidity as the end point, ten centres have reported fatality rates. Six centres out of the ten showed a statistically significant reduction in mortality in patients receiving SDD versus control. A recent French study describes the eradication of an outbreak of a multi-resistant Klebsiella with SDD. The Paris trial suggests a major impact of the SDD maneuver on the ICU ecology. Emergence of resistance to the SDD agents among gram-positive cocci has been described, although the clinical impact of this antibiotic side effect has not been reported so far. There are three indications for SDD, as follows: (i) trauma patients; (ii) liver transplant recipients and (iii) outbreaks of multi-resistant organisms.